Is there a difference beteen fuel pump arms on the A15/14 units and the A12 units?

Not so much in the performance of the unit but rather the length and design of the pump arm.

yea my A14 one has a longer pump arm than the 12 one iv got

A12 and A15 pump is the same.

Quote:
at least that's what it says. Dunno if it's true

I have later A12 with an A15 pump and it has damaged the lobe/cam slightly. Looking at the two the arm is certainly longer on the A15 pump, so in my instance that quote is wrong. No biggie, have already resorted to an A12 pump again.

I also have a feeling that my pump didn't have one of those phenolic spacers as well...

There are two A12 engines, and they are very different from each other.

Yes I noticed this when I put my two blocks together, side by side (both were the later type) first, most obvious difference was the location of the engine number stamp. Then there were a few other differences.